1. Field of the Invention
The present invention relates to a method for manufacturing semiconductor chips while supporting a semiconductor wafer by use of a support substrate.
2. Related Art
The semiconductor wafer is formed with a plurality of circuits, such as ICs or LSIs. By dicing the wafer along streets on the surface thereof, the wafer is separated into a plurality of semiconductor chips that are to be used on a variety of electronic appliances.
The semiconductor wafer is formed in a desired thickness by grinding at the back surface thereof. Recently, in order to reduce the size and weight of electronic appliances, the semiconductor wafer is necessarily worked to a thickness of 100 μm or smaller, or 50 μm or smaller.
However, there is a setback that the thinned semiconductor wafer is as flexible as paper and hence is difficult to handle after grinding. For this reason, the semiconductor wafer is ground in a state bonded on a rigid support substrate, thereby facilitating the subsequent handling including transport (see JP-A-2002-76101, for example).
However, in order to dice a post-grinding semiconductor wafer, the semiconductor wafer bonded on a support substrate must be stripped off and re-bonded onto a dicing tape into one body with a dicing frame. Because the ground semiconductor wafer is reduced in thickness, the semiconductor wafer, particularly ground to a thickness of 100 μm or smaller, or 50 μm or smaller, is readily damaged when detached from the support substrate and re-bonded onto a dicing tape. Thus, there is a problem that it is difficult to re-bond a semiconductor wafer without causing damage.
Meanwhile, in the technique of so-called pre-dicing in which grooves of a predetermined depth are previously formed along the streets in a semiconductor wafer and the back surface thereof is ground until the grooves are surfaced thereby dividing the wafer into a plurality of semiconductor chips, there is a need, prior to grinding, to bond the grooved semiconductor wafer on a rigid support substrate through an adhesive layer comparatively low in adhesion force, and, after grinding, to pick up semiconductor chips divided from the support substrate. In this case also, it is difficult to strip the semiconductor chips from the support substrate without causing damage.
Thus, it is an object of the present invention that, in the case of manufacturing thin semiconductor chips, the chips can be stripped from the support substrate without damage to the semiconductor wafer or semiconductor chips.